CODEWITHSUNDEEP
python
John Frames
John Frames

Reputation: 79

Why can a function change an objects variable but not a variable

Here's what I don't understand, if I made a function that would change the value of a variable, this would only save it in the function, so it won't change the global variable.

var = 10

def change_var(variable):
    variable += 1

change_var(var)

print(var)
________________________

10

However, when I use the variable of a object (I'm not sure what this is called), it works completely fine. This just doesn't makes sense to me that one works but the other doesn't. This is what I mean

class foo():
    def __init__(self, var):
        self.var = var

object_ = foo(10)

def change_var(object_):
    object_.var += 1

change_var(object_)

print(object_.var)
________________________

11

I want an explanation on why one works but not the other

Upvotes: 0

Views: 847

Answers (1)

Aganju
Aganju

Reputation: 6395

Python passes variables by Value, but objects by Reference.
So if you modify a variable, you modify your local copy, not the original; if you modify an object, you modify the original.

Upvotes: 2

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